(1) Field of the Invention
The present invention concerns a device and method for the volume reduction and fluidising of snow, to evacuate snow accumulated on roadways in public places or at industrial and airport sites.
The present invention relates to the general field of the volume reduction of snow subsequent to storms in places of large surface area and where clearing and return to operating service must be very rapidly obtained.
The places concerned are chiefly airports and aerodromes but also all surfaces in public places which require the clearing of accumulated snow so that normal working conditions can be resumed.
Airports, inter alia, have surface areas in the order of several million m2 which represents several hundred thousand m3 of snow to be evacuated before return to normal operating conditions. Evacuation must be carried out within a very short time and can be envisaged in 1 to 3 days. This is currently achieved using heavy construction machinery such as diggers and dump trucks sometimes requiring the transfer of snow over long distances.
One of the problems that arises is the volume of snow involved requiring the snow to be stored at a place far from the clearing site. In particular the removed snow must not be stockpiled on the edge of runways to prevent the accumulation of water which will turn to mud causing a hazard for aircraft. A second problem concerns the maximum permissible height on the side of runways which must be heeded for airport operation. This permissible height is not compatible with the volumes of snow under consideration under snowy weather conditions.
On account of the volume of snow involved, the amount of machinery and the number of loading/transport/tipping cycles at an adapted storage place are relatively high and fast snow-clearing methods prove to be extremely costly.
A further problem is related to the fact that evacuated snow contains pollutants such as fuel as well as trash or various solid objects such as pieces of tyres or various dirt items.
The problems of snow-clearing also affect winter tourist sites such as ski resorts and industrial sites such as oil installations and gas production installations in northern or polar regions where weather conditions can lead to the formation of snow drifts on installations and buildings making them impracticable and/or inoperable and even inaccessible in some cases.
At the present time, in practice, these constraints are dealt with by melting the snow with change of physical state, from ice state to liquid state by phase change, via heating which entails high energy consumption due to phase change, notably involving energy from fossil sources such as gas, coal and petroleum leading to strong emissions of greenhouse gas which place in doubt operations conducted in urban areas or polar regions on account of the damage to the ecosystem caused by these snow melting treatments.
(2) Description of the Related Art
In particular it is known from US 540 026, US 2008/0178866 or WO/038595, to store and heat snow using different ordinary heating means in a surface enclosure, and to recover the water.
Document U.S. Pat. No. 4,697,572 describes a hopper equipped with snow comminution means combined with water injection means, the liquid being evacuated to a sewer line.
The device in U.S. Pat. No. 4,697,572 uses large quantities of mains water for the mechanical obtaining of a mixture. The mains water is consumed in large quantities and discharged in the form of a water/snow slurry. This entails an expensive waste of mains water calories.
The disadvantages of current methods are due to the fact that the volumes of snow involved require storage in large-volume enclosures or tanks, hence positioned at a distance from the clearing site, whilst at the same time on account of the volume of snow involved the machinery required and number of loading/transport/tipping cycles between the clearing site and the storage place are relatively high, which means that available snow clearing methods are relatively lengthy and costly.
It is therefore the objective of the present invention to provide snow clearing devices and methods allowing facilitated transport and fastest possible reduction of snow volume for evacuation thereof, so as to limit extremely costly operating stoppages at low cost. More particularly, the objective is to allow a reduction in volume of snow accumulated on large surface areas which must be made operational very rapidly and to evacuate and/or store the snow in liquid form in reservoirs of limited volume so that they can be easily installed in the vicinity of sites at risk to limit the distance to be traveled by snow-clearing vehicles.